
//md5加密工具
let _md5 = function () {

  "use strict";

  //十六进制输出格式。0-小写；1-大写
  let __hex_case = 0;
  //base-64填充字符。
  let __b64pad = "";
  //每输入字符位数。8-ASCII；16-Unicode
  let __char_bit = 8;

  //加整数，在2^32处换行。这在内部使用16位操作来解决某些JS解释器中的错误。
  let __safe_add = function (x, y) {
    let lsw = (x & 0xFFFF) + (y & 0xFFFF);
    let msw = (x >> 16) + (y >> 16) + (lsw >> 16);
    return msw << 16 | lsw & 0xFFFF;
  };

  //按位向左旋转32位数字。
  let __bit_rol = function (num, cnt) {
    return num << cnt | num >>> 32 - cnt;
  };

  //如果一个字符的字符串被忽略，那么就把一个字符串转换成一个字符串。
  let __str_to_binary = function (str) {
    let bin = Array();
    let mask = (1 << __char_bit) - 1;
    for (let i = 0; i < str.length * __char_bit; i += __char_bit)
    bin[i >> 5] |= (str.charCodeAt(i / __char_bit) & mask) << i % 32;
    return bin;
  };

  //将一个小尾数词数组转换为字符串
  let __binary_to_str = function (bin) {
    let str = "";
    let mask = (1 << __char_bit) - 1;
    for (let i = 0; i < bin.length * 32; i += __char_bit)
    str += String.fromCharCode(bin[i >> 5] >>> i % 32 & mask);
    return str;
  };

  //将一个小尾数词数组转换为十六进制字符串。
  let __binary_to_hex = function (binary) {
    let hex_tab = __hex_case ? "0123456789ABCDEF" : "0123456789abcdef";
    let str = "";
    for (let i = 0; i < binary.length * 4; i++)
    {
      str += hex_tab.charAt(binary[i >> 2] >> i % 4 * 8 + 4 & 0xF) + hex_tab.charAt(binary[i >> 2] >> i % 4 * 8 & 0xF);
    }
    return str;
  };

  //将小尾数字数组转换为以64为基数的字符串
  let __binary_to_b64 = function (binary) {
    let tab = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
    let str = "";
    for (let i = 0; i < binary.length * 4; i += 3)
    {
      let triplet = (binary[i >> 2] >> 8 * (i % 4) & 0xFF) << 16 |
      (binary[i + 1 >> 2] >> 8 * ((i + 1) % 4) & 0xFF) << 8 |
      binary[i + 2 >> 2] >> 8 * ((i + 2) % 4) & 0xFF;
      for (let j = 0; j < 4; j++)
      {
        if (i * 8 + j * 6 > binary.length * 32) str += __b64pad;else
        str += tab.charAt(triplet >> 6 * (3 - j) & 0x3F);
      }
    }
    return str;
  };

  //这些函数实现算法使用的四个基本操作。
  let __md5_cmn = function (q, a, b, x, s, t) {return __safe_add(__bit_rol(__safe_add(__safe_add(a, q), __safe_add(x, t)), s), b);};
  let __md5_ff = function (a, b, c, d, x, s, t) {return __md5_cmn(b & c | ~b & d, a, b, x, s, t);};
  let __md5_gg = function (a, b, c, d, x, s, t) {return __md5_cmn(b & d | c & ~d, a, b, x, s, t);};
  let __md5_hh = function (a, b, c, d, x, s, t) {return __md5_cmn(b ^ c ^ d, a, b, x, s, t);};
  let __md5_ii = function (a, b, c, d, x, s, t) {return __md5_cmn(c ^ (b | ~d), a, b, x, s, t);};

  //计算一个小尾数词数组的MD5，以及一个位长度
  let __core_md5 = function (x, len) {
    /* append padding */
    x[len >> 5] |= 0x80 << len % 32;
    x[(len + 64 >>> 9 << 4) + 14] = len;

    let a = 1732584193;
    let b = -271733879;
    let c = -1732584194;
    let d = 271733878;

    for (let i = 0; i < x.length; i += 16)
    {
      let olda = a;
      let oldb = b;
      let oldc = c;
      let oldd = d;

      a = __md5_ff(a, b, c, d, x[i + 0], 7, -680876936);
      d = __md5_ff(d, a, b, c, x[i + 1], 12, -389564586);
      c = __md5_ff(c, d, a, b, x[i + 2], 17, 606105819);
      b = __md5_ff(b, c, d, a, x[i + 3], 22, -1044525330);
      a = __md5_ff(a, b, c, d, x[i + 4], 7, -176418897);
      d = __md5_ff(d, a, b, c, x[i + 5], 12, 1200080426);
      c = __md5_ff(c, d, a, b, x[i + 6], 17, -1473231341);
      b = __md5_ff(b, c, d, a, x[i + 7], 22, -45705983);
      a = __md5_ff(a, b, c, d, x[i + 8], 7, 1770035416);
      d = __md5_ff(d, a, b, c, x[i + 9], 12, -1958414417);
      c = __md5_ff(c, d, a, b, x[i + 10], 17, -42063);
      b = __md5_ff(b, c, d, a, x[i + 11], 22, -1990404162);
      a = __md5_ff(a, b, c, d, x[i + 12], 7, 1804603682);
      d = __md5_ff(d, a, b, c, x[i + 13], 12, -40341101);
      c = __md5_ff(c, d, a, b, x[i + 14], 17, -1502002290);
      b = __md5_ff(b, c, d, a, x[i + 15], 22, 1236535329);

      a = __md5_gg(a, b, c, d, x[i + 1], 5, -165796510);
      d = __md5_gg(d, a, b, c, x[i + 6], 9, -1069501632);
      c = __md5_gg(c, d, a, b, x[i + 11], 14, 643717713);
      b = __md5_gg(b, c, d, a, x[i + 0], 20, -373897302);
      a = __md5_gg(a, b, c, d, x[i + 5], 5, -701558691);
      d = __md5_gg(d, a, b, c, x[i + 10], 9, 38016083);
      c = __md5_gg(c, d, a, b, x[i + 15], 14, -660478335);
      b = __md5_gg(b, c, d, a, x[i + 4], 20, -405537848);
      a = __md5_gg(a, b, c, d, x[i + 9], 5, 568446438);
      d = __md5_gg(d, a, b, c, x[i + 14], 9, -1019803690);
      c = __md5_gg(c, d, a, b, x[i + 3], 14, -187363961);
      b = __md5_gg(b, c, d, a, x[i + 8], 20, 1163531501);
      a = __md5_gg(a, b, c, d, x[i + 13], 5, -1444681467);
      d = __md5_gg(d, a, b, c, x[i + 2], 9, -51403784);
      c = __md5_gg(c, d, a, b, x[i + 7], 14, 1735328473);
      b = __md5_gg(b, c, d, a, x[i + 12], 20, -1926607734);

      a = __md5_hh(a, b, c, d, x[i + 5], 4, -378558);
      d = __md5_hh(d, a, b, c, x[i + 8], 11, -2022574463);
      c = __md5_hh(c, d, a, b, x[i + 11], 16, 1839030562);
      b = __md5_hh(b, c, d, a, x[i + 14], 23, -35309556);
      a = __md5_hh(a, b, c, d, x[i + 1], 4, -1530992060);
      d = __md5_hh(d, a, b, c, x[i + 4], 11, 1272893353);
      c = __md5_hh(c, d, a, b, x[i + 7], 16, -155497632);
      b = __md5_hh(b, c, d, a, x[i + 10], 23, -1094730640);
      a = __md5_hh(a, b, c, d, x[i + 13], 4, 681279174);
      d = __md5_hh(d, a, b, c, x[i + 0], 11, -358537222);
      c = __md5_hh(c, d, a, b, x[i + 3], 16, -722521979);
      b = __md5_hh(b, c, d, a, x[i + 6], 23, 76029189);
      a = __md5_hh(a, b, c, d, x[i + 9], 4, -640364487);
      d = __md5_hh(d, a, b, c, x[i + 12], 11, -421815835);
      c = __md5_hh(c, d, a, b, x[i + 15], 16, 530742520);
      b = __md5_hh(b, c, d, a, x[i + 2], 23, -995338651);

      a = __md5_ii(a, b, c, d, x[i + 0], 6, -198630844);
      d = __md5_ii(d, a, b, c, x[i + 7], 10, 1126891415);
      c = __md5_ii(c, d, a, b, x[i + 14], 15, -1416354905);
      b = __md5_ii(b, c, d, a, x[i + 5], 21, -57434055);
      a = __md5_ii(a, b, c, d, x[i + 12], 6, 1700485571);
      d = __md5_ii(d, a, b, c, x[i + 3], 10, -1894986606);
      c = __md5_ii(c, d, a, b, x[i + 10], 15, -1051523);
      b = __md5_ii(b, c, d, a, x[i + 1], 21, -2054922799);
      a = __md5_ii(a, b, c, d, x[i + 8], 6, 1873313359);
      d = __md5_ii(d, a, b, c, x[i + 15], 10, -30611744);
      c = __md5_ii(c, d, a, b, x[i + 6], 15, -1560198380);
      b = __md5_ii(b, c, d, a, x[i + 13], 21, 1309151649);
      a = __md5_ii(a, b, c, d, x[i + 4], 6, -145523070);
      d = __md5_ii(d, a, b, c, x[i + 11], 10, -1120210379);
      c = __md5_ii(c, d, a, b, x[i + 2], 15, 718787259);
      b = __md5_ii(b, c, d, a, x[i + 9], 21, -343485551);

      a = __safe_add(a, olda);
      b = __safe_add(b, oldb);
      c = __safe_add(c, oldc);
      d = __safe_add(d, oldd);
    }

    return Array(a, b, c, d);
  };

  //计算一个密钥和一些数据的HMAC-MD5
  let __core_hmac_md5 = function (key, data) {
    let bkey = __str_to_binary(key);
    if (bkey.length > 16) bkey = __core_md5(bkey, key.length * __char_bit);

    let ipad = Array(16),
      opad = Array(16);

    for (let i = 0; i < 16; i++)
    {
      ipad[i] = bkey[i] ^ 0x36363636;
      opad[i] = bkey[i] ^ 0x5C5C5C5C;
    }

    let hash = __core_md5(ipad.concat(__str_to_binary(data)), 512 + data.length * __char_bit);
    return __core_md5(opad.concat(hash), 512 + 128);
  };

  //实例
  let __instance = null;
  //接口类
  let Class = function () {};

  //实现单例
  let GetInstance = function () {
    if (__instance == null)
    {
      __instance = new Class();
    }
    return __instance;
  };

  //对外接口，接受字符串参数并返回十六进制或base-64编码的字符串
  Class.prototype._hex_md5 = function (s) {return __binary_to_hex(__core_md5(__str_to_binary(s), s.length * __char_bit));};
  Class.prototype._b64_md5 = function (s) {return __binary_to_b64(__core_md5(__str_to_binary(s), s.length * __char_bit));};
  Class.prototype._str_md5 = function (s) {return __binary_to_str(__core_md5(__str_to_binary(s), s.length * __char_bit));};
  Class.prototype._hex_hmac_md5 = function (key, data) {return __binary_to_hex(__core_hmac_md5(key, data));};
  Class.prototype._b64_hmac_md5 = function (key, data) {return __binary_to_b64(__core_hmac_md5(key, data));};
  Class.prototype._str_hmac_md5 = function (key, data) {return __binary_to_str(__core_hmac_md5(key, data));};

  //执行一个简单的自检，看看虚拟机是否正常工作
  Class.prototype._md5_vm_test = function () {return this._hex_md5("abc") === "900150983cd24fb0d6963f7d28e17f72";};

  //返回
  return GetInstance();

}();

//导出函数
export default _md5;